Acoustical construction



Oct.. 30, 1,934. L. R. HOFF E1' AL A COUSTICAL CONSTRUCTION" Filed Jan. 25,' 1932 mvlamonsy Y Louw 1a Hoff.

Patented Oct. 30, 1934 A AcoUs'rIcAL coNs'rrmc'rloivl f Lodis n, Hoff, New Rochelle, and George 1).V

Kellogg,

Pelham .Manon N. Y.assignors to Johns-Manville Corporation, New York, N. Y.,

a corporation of New York Application January 25,

9 Claims.'

The present invention relates to improvements in acoustical construction, and particularly to such a construction units. One cf the outstanding disadvantages in the conventional constructions employed for acoustical Vtreatment resides in their lack of certain-of the qualities necessary for exterior surfaces of a wall or ceiling.' For most purposes it is highly lo'desirable that such surfaces be permanent and `fireproof in character, readily cleaned and painted, and decorative and pleasing in appearance. Conventional types of acoustical or soundabsorptive materials such as felts of fibrous material, or molded masses of mineral wool associated with a binding material, lack one or more of the comprising preassembled properties desirable in an exterior finish, and consequently for the most part acoustical construcposed of molded masses of mineral woolassociated' with a binder,are very efficient from the ste-ndpoint of acousticaljeffectiveness, but due to their inherent frangibility such products are subjected lto a relatively large breakagefand furthermore yare characterized by surfaceswhich do not lend themselves readily to decorative treatment or cleaning. Y One of the objects of this invention is the provision of a structure wherein frangble sound-absorptive material of the type `mentioned is reinforced with a facing material which renders it capable of being readily applied in unit form and which facing also prevents breakage and obviates other disadvantages inherent in the 354 soundabsorptive material employed.

Another object of the invention is the provision of anfacoustical construction of high acoustical efficiency wherein the surface of the element directly exposed to the impinging sound is of a per- 40 marient and iireproof character, readily cleaned and painted, and having a pleasing and decorative appearance.

A rurtherf object of the invention is the pro- .vislon of an acoustical unit ywhich may be readily 4 vand economically installed.

Variousother'objects and advantages of the invention willbe evidentfrom the following de- 'scription of an illustrative andzpreferred embodiment shown in the accompanying drawing,

wherein: i i

Fig. 1 is a plan view of the preassembled unit taken from the back; A Fig.` `2 is a sectional view of a plurality of the units combined with a ceiling substructure; i

1932, serial No. 588,516

(c1. zii-4) Fig. 3 is a sectional view of the unit taken along line A--A of Fig. l; and

Figs. 4 and 5 disclose a modification of the invention.

The unit shown in detail in Figs. l and 3 com- 60 prises 4a perforated facing member l and a backing member 2 contiguous to the facing member comprising a block or pad of sound-absorptive material. The facing and backing members are maintained in an assembled relation by suitable fastening means such as staples 3 which are .driven through apertures 4 in the facing into the pad. The apertures are preferably countersunk as shown so that the head of the fastening element is flush with the surface. The staple employed is of sufficient length to permit each prong to be bent, thereby `forming laterally extending portions 5 contacting theback of pad 2 and serving to maintain the entire unit in anassembled relation.

The units'may be combined with any type of 75 wall or ceiling surface to be acoustically treated as shown in Fig. 2. In this figure arceilng or wall substructure which may be plaster, iathing or any `other suitable material is indicated generally by `numeral 6.- Nailing'strips 7 are affixed to the so substructure at spaced intervals corresponding to the dimensions of the individual units. Each unit is disposed so that the apertures 8 in the facing member are in alignment with the underlying strips '7 and is secured in position by fastening 85 means such as nails 9 driven throughthe aper. tures into strips Thestaples 3 are so disposed that the bottom portion thereof is in contact with the bottom portion of strips, whereby they function to maintain the facing member at a fixed distance in spaced relationship with the substructure and in alignment with adjacent units. As

shown, adjacent units are preferably disposed so that the facing members and sound-absorbing backings are in aligned, abutting relationship. Ininstalling the units the marginal portions of rthe sound-absorptive backing which projects slightly beyond the edges of the facing portion, as shown in Fig. 2, are compressed against corresponding marginal 'portions of adjacent units wherebya tight t between adjoining units is insured. It will be noted that the construction provides for a tight fit between adjacent units and for an abutting contact of the edge portions of the sound-absorbing material of adjacent units. This construction is especially advantageous in that it obviatesV the circulation of air in,large quantitiesthrough the joints due to breathing caused by temperature fluctuations and the re- 110 and hence is'especially reproof.

vinto facing units of the requisite size.

of employing laminated asbestos-cement sheets,

sulting deposition of dirt on the surface of the facing member adjacent the joint.

For the sound absorptive backing 2 there are preferably employed molded sheets or blocks'of mineral wool associated with a suitable binder. Such products are highly efficient sound absorbers, and the disadvantages arising from their inherent frangibillty and tendency to dust and disintegrate are obviated by the reinforcement imparted by the facing member. Various other kinds of sound-absorptive material, however, may be employed to advantage in the practice of the invention other thanfrangible blocks.

The facing member is preferably composed of dense, rigid or self-sustaining material in contradistinction, for instance, to porous, fiexible mate-l clude about 15-20% of asbestos fibers, and about In manufacturing SCI-85% of Portland cement. these sheets, a pulp of theAfibrous-cement mixture is formed into a felted web on a suitable felting device and the web wound on a mandrel until it forms a laminated cylinder of the desired thickness. This cylinder is then cut longitudinally and developed into sheet form. After drying Vthe sheet may be impregnated with a suitable waterproofing material. Sheets thus made are prof vided with suitable perforations 13 and then cut In place as described above, sheets oi the same constituents but varying in their proportions and fabricated by molding under pressure such as Transite may be used. Various other types of sheet material may be employed for the facing member in addition to the asbestos-cement products above mentioned, the most important requirement being that the sheet is structurally strong and is of a self-sustaining or rigid character, in contradistinction to materials such as fabrics and the like. A facing member composed of an asbestos-cement composition is particularly advantageous, however, in that thepresulting product is non-corrosive and non-rusting and consequently may be employed in kitchens and other places Where humid conditions prevail.

The number and size of the perforations 13 are subject to considerable variations. lIn general the number of perforations is restricted to a minimum compatible with thev attainment of the desired degree of acoustical efficiency. For a facing having a thickness of 1% inch, a perforated area of 10% consisting of uniformly spaced perforations of a diameter of 11/64 has been found to be entirely satisfactory.v

Figs. i and 5 represent a modification of the invention which obviates the use of nailing strips, In this ernbodiment the assemblageis secured by an adhesive, as, for instance, a conventional form of acoustical cement, Portland cement, plaster of Paris, or the like, which is applied between the fastening means and substructure. In this construction a perforated washer l1 is preferably associated with the fastening means as shown to provide a more effective bond for the adhesive.

remesa Sound-absorption tests on a ceiling acoustically treated in accordance with the invention gave the following results,

Cycles 128 Coeiilcient i9 From the above test Yit will be apparent that ventional types ofsurface finishes.

, What we claim is: 1. A pre-assembled acoustical unit comprising a perforated facing member of rigid dense sheet material, a sound-absorbing pad contiguous to the facing member, and means extending through the facing member and pad to maintain said ele ments in assembled relation. y

2. A pre-assembled acoustical unit comprising a perforated facing member yof rigid dense sheet material, a sound-absorbing padl contiguous to the facing member, and mechanical fastening means extending through the facingr member and pad to maintain said elements in assembled relation.

3. A pre-assembled' acoustical unit comprising a frangible sound-absorptive blockga protective reinforcing facing o f perforated, dense, rigid sheet material adjacent'said block,Y and securing means extending through said block and facing to maintain said elements in a unitary construction whereby the frangible soundeabsorptive material is protected'against breakage and rendered ca-v in assembled relation.

5. Al pres-assembled acoustical unit comprising a sound-absorptive'mol'ded block of mineral vwool and a binder, a reinforcing facing secured to said block consisting of perforated sheet formed from a mixture of asbestos and cement, and securing means passing through said block and facing to maintain said elements in assembled relation.

6,. A pre-assembled ,acoustical unit comprising Va frangible sound-absorptive molded block of formed from a mixture including lasbestos and. f cement, and having a minimum average thickness of not less than one eighth of an inch,` and secur- 'ing meanspassing through said block and facing to maintain said elements in an assembled relation. v

7. In an acoustical construction, the combination of a perforated facing member of self-sustaining materia-l, a sound-absorbing pad contiguous to the facing member, and means for assembling the pad and facing member including spacing means projecting through the pad for maintaining the facing member at a fixed distance from the back surface of the pad.

8. In an acoustical construction, the combination of ya perforated facing member of self-sustaining material having openings therein for the reception of fastening elements, a'pad of soundf 'absorptive material contiguous to the facing reception of fastening elements, a pad of soundabeorptive material contiguous to the facing member, and means for assembling the pad and facing member comprising fastening elements extending through the openings in the facing member into the pad, and an adhesive material disposed between and securing the fastening element and substructure.

LOUIS R. HOFF.

GEORGE D. KELLOGG.

lnu 

